Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is a front view thereof in a second state;

FIG. 3 is a front view thereof in a third state;

FIG. 4 is a front view thereof in a fourth state;

FIG. 5 is a front view thereof in a fifth state; and,

FIG. 6 is a front view thereof in a sixth state.

The broken line at the periphery of the figure illustrates the display screen or portion thereof, and the remainder of the broken lines illustrate portions of the transitional graphical user interface. None of the broken lines form part of the claimed design.

The outermost broken line showing the display screen is for environmental purposes only and forms no part of the claimed design.

The appearance of the transitional user interface sequentially transitions between the images shown in FIGS. 1-6. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 